This invention relates to a toll paying system for use with a turnpike/toll road toll booth, and more particularly to a toll paying system for use with a vehicle passing through a fast lane having a toll booth having electronic means for paying a toll.
1. Description of the Prior Art
The highway and roadway systems in the United States are the main transportation thoroughfares in America today. Millions of citizens use the highways on a daily basis. Traffic density is particularly acute during commuter rush hour due to the large percentage of the population which utilizes the roadways during peak hours. Faced with the task of funding certain bridges, tunnels, and arteries, many states and cities have for years chosen the fair policy of obtaining revenue for these costly facilities from the motorists and commercial traffic which use them. As a result hundreds of toll stations exist, most of which are located on the East Coast of the United States. Yet these payment collection sites, which are the economic lifeblood of the Highway Authority, are themselves the root cause of extreme problems, simply because the traffic must come to a complete stop in order to render payment. The overwhelming bottleneck associated with certain existing toll stations is best summarized from factual verifiable examples of several representative situations.
As an example of the problem, consider data collected at the Tappan Zee Bridge during morning rush hour on Wednesday, July 13, 1988, which is typical of normal work days. Weather was sunny, 70.degree.. With all 13 toll lanes open, it took between 17 to 20 minutes for vehicles to progress through the line of stopped traffic waiting to move up to the toll booths. During the period between 7:15 a.m. and 8:45 a.m. a minimum of 2000 vehicles were counted, stopped in line and for a period, more than 4000 vehicles were counted.
The throughput rate of all 13 toll lanes combined was counted to be as follows. Some minutes experienced a rate of 60 to 70 vehicles per minute; other minutes experienced rates of 70 to 90 vehicles per minute; other minutes experienced 90 to 110 vehicles per minute; very occasionally was there a minute with over 110 vehicles per minute. This is the aggregate sum of all 13 toll lanes combined. The rate depends on whether drivers have exact change, how many 18 wheel tractor tailors are present, etc. An example of a "per lane" rate is as follows: For a minute with 91 vehicles for all 13 lanes, the average per lane rate is 91/13=only 7 vehicles per minute for one toll lane.
On the Tappan Zee Bridge, note that toll points exist only in west to east direction. The amount of fuel that is consumed by thousands upon thousands of vehicles that travel at 55 m.p.h., come to a full stop, stop and go for more than 17 to 25 minutes, and then accelerate back up to 55 m.p.h. can only be estimated. However even extremely conservative estimates would be dramatic in light of the fact it happens during morning and evening rush hours, each working day, all year round, year after year after year. The deleterious consequences of this extends to the environment in that the congestion in the air due to the incredible build up of carbon monoxide and other lethal engine exhausts which plague the people waiting in line as well as the staff of toll collection agents. The impact also is in terms of international trade imbalance since some of this massive amount of fuel is purchased outside of the United States.
The amount of cumulative time spent by members of the United States population in simply waiting in a stopped line to pay traffic tolls is staggering. An example of this is as follows. Although many thousands of motorists use the Tappan Zee Bridge during each commute, the number 2000 will be used purely for illustrative purposes. Conservative numbers will be used. Fifty weeks per year will be used to account for vacation.
(2000 motorists).times.(0.25 hours stopped per commute).times.(twice per day).times.(5 days per week).times.(50 weeks per year)=250,000 hours per year. In fact the actual number is millions of hours per year spent by members of the United States population waiting in line.
As another example, consider the Maine Turnpike. The information reported here was announced on commercial radio stations in Portland, Me. the day after Memorial Day Weekend, 1988.
During the late afternoon and into the evening of May 30, 1988, a monumental traffic jam in the southbound direction of the Maine Turnpike was caused by the toll stations at the southern most point of the highway. The traffic jam was the result of tens of thousands of motorists leaving the Pine Tree State all at the same time and returning to their homes at the end of the Memorial Day Holiday weekend. For several hours traffic was virtually stopped for a length of 40 miles, from Biddeford to Kittery. This traffic jam is part of the repeating pattern which manifests itself at the closing hours of all major holidays throughout the year in Maine, Vacationland.
As a further example of the problem, consider the Pennsylvania Turnpike. The information reported here was broadcast on television stations in Washington, D.C. At the beginning and at the end of the Thanksgiving Weekend, 1988, there were significant delays for motorists at certain toll points on the Pennsylvania Turnpike.
Another example of the problem is the Massachusetts Turnpike. Data were collected during 1985 while commuting on the Mass Pike during rush hour during every working day, except vacation, of that year. The toll station on the Massachusetts Turnpike, Route 90, at the exit point for Route 128 typically introduced a wait of over 3 minutes. However many times the delay was as long as 5 or 8 minutes. There also were days when it was longer.
For the Tobin Bridge, Boston, Mass., information has been reported live during rush hour over WBZ Radio. Every working day during both commutes there is a delay at the toll stations on the Tobin Bridge.
Elsewhere, the Governor of Maryland in 1989 ordered the closing of one direction of the toll stations on the route 50 bridge near Annapolis due to the overwhelming agglomerative traffic jam every rush hour.
Along interstate 95, between Philadelphia and the Nation's Capitol there are three toll collection sites. At each site there are consistent delays at the toll stations during each rush hour commute.
Many other examples could be given such as the Garden State Parkway, New Jersey turnpike, and toll tunnels.
The problem actually goes deeper than how it appears on the surface. Certain high population centers in the United States are presently seeking huge amounts of cash to pay for existing roadway maintenance and to fund urgently needed new highways. These communities presently do not have toll roads because tolls may be out of the question due to the traffic jams. This is ironic because tolls charged to the vehicles that use the roads are a way to pay for them. Real estate tax increases may be unfair for additional road development because the taxpayer seldom would pay a dollar amount proportional to approximating his/her personal use of the roads. Furthermore, many people outside the tax base also use the roads. Funding from the Federal Government for road repairs appears difficult due to the monstrous deficit.
Examples of geographic regions which are seeking funds for roadway construction and maintenance include Fairfax, Va., where the Fairfax County Board of Supervisors has announced that Fairfax Co. must raise one hundred million dollars additional revenue per year to fund roadway development. This development is urgently needed due to the explosive growth that is being experienced in Fairfax Co. More than one billion dollars reportedly is required for road system development.
The Fairfax Journal Newspaper during 1989 has run front page articles several times a week about the roadway problem and funding. The usual proposals are real estate tax, gas tax, or reduction of revenues of other programs. For example, the front page of Apr. 21, 1989 speaks of obtaining highway funding by slashing county money currently providing "medical care for sick children".
The private sector is addressing a subset of the problem. The Dec. 29, 1988 edition of the Washington Post reported that a company is seeking authorization for a Dulles Toll Road extension. Expected toll revenues are from 70 thousand vehicles for each commute. The same company is offering to refurbish the Wilson Bridge, notorious for massive traffic flow, and to pay for it by establishing tolls.
Routes 495 and 95, the Beltway around Washington, D.C., is an example where the television stations have reported that transportation planners are seeking massive amounts of money to pay for improvements to the Beltway. The option of tolls has been considered. Public discussion has been held to consider the possibility of constructing another beltway and/or bypass to relieve the unacceptable congestion and density that presently exists on the beltway. Television stations report that during each commute more than 700,000 vehicles use the beltway, every working day.
Washington, D.C. television station, WETA, announced the results of a viewer survey poll about how to pay for desperately needed roads. The report of December 1988 listed categories including tolls only; tolls plus certain taxes; etc. Forty-seven percent of the viewers chose tolls in one form or another. Yet this was with the knowledge that extremely long lines would develop. It is assumed that higher percentages would result if it is known that there would be no waiting. Undoubtedly, the percentage would drop to zero if the television audience were told that conventional toll booths would be used and the expected line on the Capitol Beltway will be 50 to 125 thousand cars at each toll station and the wait will be 20 hours per car. ((125,000 cars)/(100 cars/minute)).times.(1/60 hour/minute)=20.83 hours. This will indeed be the wait if the same traffic throughput is realized as is presently experienced on the Tappan Zee Bridge.
The nationally syndicated television program "Adam Smith's Money World", during December 1988, ran a story concerning roadway improvement. Top government executives were interviewed. The program ended with Adam Smith saying "it appears many or most roads will become toll roads".
2. Prior Art Approaches
In the prior art, a number of systems have been proposed for paying tolls at a toll booth using transponders and other radio techniques. See U.S. Pat. No. 4,303,904 to Chasek, which is incorporated herein by reference. Such prior art systems have problems with the base station illuminating each distinct vehicle transponder sequentially. In order to prevent simultaneously "illuminating" more than one vehicle, an extraordinary electromagnetic field density gradient would be used, when vehicles are close together. This gradient may be in excess of 100 dB per 15 feet for acceptable probability of detection and probability of false alarm performance in theoretical receiver operating characteristics curves. Having a gradient of much greater than 100 dB per 15 feet is impossible to achieve in the real world of actual traffic lanes because of specular reflection multipath and diffuse scattering multipath reflections and standing waves that occur due to closely spaced vehicles, the roadway pavement, lane dividers (jersey barriers), and "blockage", such as when it is desired to illuminate a flat front van that is 20 feet behind an 18 wheel box trailer tractor trailer truck, while preventing illumination of the vehicle behind the van.
The traffic at the toll payment entrance end of Boston's Sumner Tunnel and Callahan Tunnel, due to traffic congestion at the tunnel exit end, is often flowing at 5 or 20 miles per hour. Under this condition, two motorcycles may be separated by only one foot. The transponders, one on each motorcycle, would then be separated by 8 ft. This separation requires "well in excess of" 100 dB per 15 feet. For this example the problems are compounded due to electromagnetic field density fluctuations caused by metal surfaces of small vehicles such as "California Shorts", Volkswagen Bugs, and 1932 Deuce Coupes.
In the prior art a technical approach of using only one frequency for vehicle transponder signals is used. Problems with this approach are that toll payment stations which use more than one traffic lane as "electronic toll payment lanes" experience co-channel frequency interference since transponders in several traffic lanes compete for use of only one frequency.
In future years, the "one frequency" may be used by other systems, including commercial communications; harmonic frequencies of television station transmitters that would be built near the toll station; would-be toll violators who would attempt to build illegal electronic instruments to pay the toll, would know what frequency to build into the equipment.
In the prior art the technical approach of using a mechanical "vehicle pass or reject mechanism" suffers practical problems. Fatal accidents can occur as a result of stopping a line of high speed traffic which is transiting through the toll payment lane. Of course, a coin cash collection basket may be at the "stop gate" for a vehicle which has been stopped due to nonpayment. A toll station attendant would have to walk out to the stopped vehicle to service the transaction to give change.
In the prior art the technical approach of using the same unique transponder digital message each time the transponder is used for all toll payments suffers practical problems. This approach lacks electronic counter measures. Would-be computer-hackers who would attempt to receive someone's signal, build an instrument to clone the signal, and use the signal illegally would be able to do so.
In the prior art the technical approach of using a "half wave distributed filter" as the RF tuning mechanism suffers practical problems. The microwave filter is recursive. The canonical structure does not yield acceptable stop band rejection. The "second order" distributed filter approximation function does not support steep attenuation skirts. The filter does not realize flat group delay. The communications link is not memoryless due to the nonlinear insertion phase filter. Flat group delay is required in digital communications in order to minimize intersymbol interference. The filter does not yield a flat pass band, thus energy is wasted. There's going to be low return loss due to a high VSWR at the input port.
In the prior art other reasons which contribute to a higher than necessary bit error rate in the real stochastic world are as follows. The tunnel diode approach suffers unnecessarily high phase noise. The available time bandwidth product is not used to capacity. The signal is neither antipodal nor orthogonal, thus prone to errors--loss of money--in lightning storms and in the presence of co-channel interference such as harmonics of a CB, ham, or other transmitter in a nearby vehicle. The presence of a clock wastes energy and time. The rectangular and trapezoidal time domain clock/signal windows give rise to a degradation in the energy density in the frequency domain. The lack of error correction further causes money to be lost. The single, once only, transponder reply denies verification, an acute problem during thunderstorms. For these reasons from a systems integrity standpoint, the covariance matrix resulting from the prior art approach is significantly greater that the inverted Fisher Information Matrix of the communications channel and as a result money is unnecessarily placed in jeopardy. Stated linearly, these ingredients for the prior art result in a bit error rate that is much worse (logarithmically 70, 80, 90 dB depending on the Hilbert Space state transition matrix) than necessary within the framework of Information Theory, Communications Theory, Stochastic Systems Theory, Optimization Theory, Multivariate Analysis Theory, Coding Theory, Estimation Theory, Electromagnetic Field Theory, Detection Theory, Microwave Theory, and the Theory of Signal Processing.